The present invention relates to an apparatus for mixing of liquid substances or distribution of solid substances in liquid substances in a plurality of sample containers arranged in a microplate that is supported on a horizontally displaceable support plate, incorporating a motor provided with unbalance and connected to the support plate, as used particularly in metrology for detection of certain substances or substance properties, e.g., by performing luminescence measurements or fluorescence measurements. This may be a matter of mixing two or more liquids, or also of attaining as homogeneous a suspension as possible. Furthermore, applications are known in bioanalysis, in which a liquid must come into contact as completely as possible with solid material on the wall of a sample container. All of this shall be understood by “mixture” in the following discussion.
In industrial or biotechnology settings, these types of measurements, as a rule, are performed using microplates, i.e., molded parts that possess a multitude of cavities in matrix-like arrangement for receiving liquid samples. Initiating a luminescence or fluorescence reaction, as a rule, requires adding at least one other, usually liquid, substance to the liquid sample in the sample wells of the microplate, so that, consequently, at least two substances are contained there in certain quantities.
Since the evaluation of luminescence/fluorescence measurements is ultimately based on a measurement of the quantity of photons, which are counted using a photon counting device (e.g., a photomultiplier), and the number of photons, in turn, depends on the number of reactions of molecular components of the at least two substances contained in the sample containers, it is crucial that, in order to achieve conclusive and reproducible measuring results, the most homogeneous thorough mixing possible of the substances in each of the sample wells of the microplate must be performed, regardless of where the sample container is located within the matrix-like arrangement of the microplate.